Wilkerson describes the segregation and racism of the South as a caste system. The specific terminology is important, because the objective of a caste system is not just to discriminate but also to fix various sets of people in relationship to each other. A caste system is all-pervasive and absolute, dictating codes of conduct for every social interaction between dominant and oppressed castes. It is as omnipresent as air or water. Because of its pervasive nature, the caste system exercises a very powerful pull, which the Southern Black migrants had to fight against to make their northbound journeys. Under the caste system, there existed not just separate washrooms for whites and Blacks but also, in certain Southern courthouses, separate Bibles for white and Black defendants to swear on. A Black man needed to step off the sidewalk if a white man approached, and at traffic lights, Black drivers were supposed to give right of way to white drivers. On trams and buses, the Black seats were the ones right at the back, as they were in cinemas.

This caste system was upheld through severe punishments. Between 1890 and 1960, even asking a white storeowner for a bill could result in a Black person’s lynching. Asking for the bill was not the crime in itself; the real crime was forgetting one’s place. In the caste hierarchy, to stray from one’s fixed place was the greatest punishable offence. A particular feature of the caste system is the idea of the other as a sexual threat to the purity of the privileged female. The other is seen as animalistic, dangerous, and a threat to racial and social purity. Thus, even the suggestion of sexual misconduct against a white woman could cause a Black man to be castrated, tortured, mutilated, or killed. The fact that poor black women were far more at threat from white men than the other way round was completely dismissed. Despite the difficulty of leaving the caste system of the Jim Crow South, its atmosphere of degradation and danger was a central motivator of the Great Migration.

The Southern Black migrants escaping the South idealized the Northern cities to which they were journeying. They imagined these cities would be meccas of equality, polar opposites of the caste-ridden South. Perhaps this idyll was necessary to propel their monumental journeys. Perhaps its myth was perpetuated by older migrants who visited the South in their best finery and told tales of their grand lives up North. Whatever the cause for the idyll, the reality was far more complex. As Ida Mae, George Starling, and Robert Pershing Foster would discover, the “mirage of equality” of the great cities of the North and West was illusory. Ida Mae’s Chicago was divided along bitter racial lines, while George’s Harlem was beset with urban crowding and class tensions. As a physician in California, Pershing would be rejected on account of his race by none other than a Black woman. Late in his life, he would be charged with inappropriate behaviour by a white woman, resurrecting the ghost of Jim Crow. Racial hatred was a feature of the North, too.

The key difference was the way racism manifested itself. While the South was openly segregated, the people of the North and West professed racial equality but carried out segregation in their daily lives. The invisible race laws of the city were hard to read for the Southern Blacks, who had grown up in a world clearly labelled “COLORED” and “WHITE.” In Chicago, Detroit, and even New York and Los Angeles, there existed race lines that confounded the...